In an image pickup device such as a single-reflex digital camera of a lens-replacement type, the use of an image pickup element (may hereunder be also referred to as a “phase-difference detecting image pickup element”) is proposed. The image pickup element includes a plurality of pairs of photoelectric converters (photodiodes) and is capable of detecting a focus by a phase difference detection method. Each pair of photoelectric converters generates corresponding image signals by receiving light beams of an object transmitted through a corresponding pair of portions (such as a left pupil portion/a right pupil portion) in an exit pupil of an interchangeable lens (shooting optical system). Known examples of the image pickup element are as follows.
For example, PTL 1 discusses a phase-difference detecting image pickup element having a structure in which photoelectric converters are divided in two in ordinary pixels (RGB pixels) used for obtaining image signals of an object (such photoelectric converters are hereunder referred to as “half-size photoelectric converters”). That is, Patent Document 1 discusses a phase-difference detecting image pickup element in which a pair of half-size photoelectric converters are disposed below one microlens.
In addition, for example, PTL 2 discusses a phase-difference detecting image pickup element in which a light beam of an object is limited at a small opening in a light-intercepting mask using a metallic layer in a pair of adjacent pixels, so that a pair of portions of the exit pupil receive the light beam at a pair of photoelectric converters.